ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
This study pays attention to reveal the material properties that control resistance curve forductile crack growth (CTOD-R curve) on the basis of the mechanism for ductile crack growth, sothat the R-curve could be numerically predicted only from those properties.The crack growth tests using 3-point bend specimens with fatigue pre-crack were conducted fortwo steels that have different ductile crack growth resistance with almost the same CTOD level forcrack initiation, whereas both steels have the same “Mechanical properties” in terms of strength andwork hardenability. The observation of crack growth behaviors provided that different mechanismsbetween ductile crack initiations from fatigue pre-crack and subsequent growth process could beapplied. It was found that two “Mechanical properties” associated with ductile damage of steelcould mainly influence CTOD-R curve; one is a resistance of ductile crack initiation estimated withcritical local strain for ductile cracking from the surface of notched specimen, and the other one is adependence of stress triaxiality on ductility obtained with circumferentially notched round-barspecimens.The damage model for numerically simulating the R-curve was proposed taking the two “ductileproperties” into account, where ductile crack initiation from crack-tip was in accordance withcritical local strain based criterion, and subsequent crack growth GTN(Gurson-Tvergaard-Needleman) based triaxiality dependent damage criterion. The proposedmodel accurately predicted the measured R-curve for the two steels used with the same “strengthproperties” through ductile crack initiation to growth
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/15/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.539-543.2186.pdf
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